Finish issue #2717 by giving svnsync support for two different sets of pre-specified authn creds (one for each of the source and destintation repositories).
Finish issue #2717 by giving svnsync support for two different sets of
pre-specified authn creds (one for each of the source and destintation
repositories).

This adds four new option to the svnsync command-line:

   --source-username, --source-password
   --sync-username, --source-password

The existing --username and --password options remain (for
compatibility).  However, you may not mix the use of --username and
--password with any of the four new options.  Also, specifying
"--username FOO" is treated under-the-hood just like
"--source-username FOO --sync-username FOO"; specifying "--password
BAR" is the same as "--source-password BAR --sync-password BAR".

* subversion/svnsync/main.c
  (svnsync_opt_source_username, svnsync_opt_source_password,
   svnsync_opt_sync_username, svnsync_opt_sync_password): New option enums.
  (sync_baton_t, init_baton_t, copy_revprops_baton_t): Lose callbacks;
    add source_callbacks and sync_callbacks.
  (SVNSYNC_OPTS_DEFAULT): Add svnsync_opt_source_username,
    svnsync_opt_source_password, svnsync_opt_sync_username,
    and svnsync_opt_sync_password.
  (opt_baton_t): Lose auth_username; add source_username and
    sync_username.  Lose auth_password; add source_password and
    sync_password.  Lose auth_baton; add source_auth_baton and
    sync_auth_baton.
  (main): Handle the new options, disallowing the intermixing of
    --username with --source-username or --sync-username and the
    intermixing of --password with --source-password or --syncpassword.
  (do_synchronize, do_copy_revprops, do_initialize): Use
    baton->source_callbacks to open the RA session to the destination
    repository.
  (initialize_cmd, synchronize_cmd, copy_revprops_cmd): Populate both
    the source_callbacks and sync_callbacks members of the
    sync_baton_t, using the related auth_baton.  Use the
    sync_callbacks to open the RA session to the destination
    repository.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@863507 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion